Tool having a spring loaded scissorlike action



July 31, 1951 J. SMYTH 2562;828

TOOL HAVING A SPRING LOADED SCISSOR-LIKE ACTION Filed Jan. 13, 1949 IN VEN TOR A TTORNf Y Patented July 31, 1951 TOOL HAVING A SPRING LOADED SCISSOR- LIKE ACTION 7 Leslie John Smyth, Thames Ditton, England Application January 13, 1949, Serial No. 70,741 In Great Britain December 18, 194'? 4 Claims.

This invention relates to tools having a spring loaded scissor-like action. In a pruning tool, for instance, the blades are maintained in the open position by a spring disposed between the handles or at a pivotal or other point as may be convenient and, when the tool is operated, the closing or shearing action is against this spring. Since the blades are spring loaded, the handles open, to the widest extent when a grip on the tool is relaxed and, in most instances, the handles are so widely separated that a fresh grip cannot be readily secured. Further, a clip or the like has to be provided for retaining the blades in the closed position when the tool is not required for use, the manipulation of this clip necessitating the use of both hands. This is a distinct disadvantage in circumstances where one hand only is available for locking and releasing the blades, as for instance, when a tree is being pruned.

The object of the present invention is, more particularly, to provide a pruning tool wherein the blades are spring loaded, but wherein the opening and closing of the blades or handles are limited and wherein means are provided whereby the blades or handles can be locked in the closed or other pre-determined position and also opened by the hand gripping the tool.

According to the present invention there is provided a tool having a scissor-like action against spring means, a pivotal connection which incorporates a spring loaded element adapted to be moved axially of the said pivotal connection, the element having one or more projections, the projection or each projection being adapted to enter apertures or slots in superposed parts of the tool adjacent the said pivotal connection, the arrangement being such that when the handles are closed together, certain of the apertures or slots are brought into alignment, thus permitting the projection or each projection to be pressed into all the apertures or slots thereby locking the handles together, the retention of the projection oreach projection being effected 'by pressure exerted by the spring loading of the I tool, means being providedwhereby this pressure may be relieved to enable the spring loaded ele-' ment to withdraw the projection or each jection and release the handles.

In order that the said invention may be clearly understood and readily carried into effect, the same will now be described more fully, by way of example, with reference to the accompanying drawings in whichz' Figure 1 is an elevation of a pruning tool incorpro 2 porating a device according to the present invention;

Figure 2 is a section on line 2-2 of Figure 1.

drawn to an enlarged scale;

Figure 3 is a perspective view of a press button forming a part of the said device;

Figure 4 shows fragmentary elevations of the members a, b, c and at indicated in Figure 2, but drawn to the same scale as thatof Figure 1; V

Figure 5 is a perspective view of a modified form of press button according to the'present invention;

Figure 6 shows fragmentary elevations of the members a and 0, corresponding to those shown in Figure 2, but furnished with modified forms of apertures;

Figure '7 is a section on line 'l'! of member 0, illustrated in Figure 6, but drawn to an enlarged scale;

Figure 8 is a perspective view showing a modification of the superposed members, and

Figure 9 is a perspective view of a modified press button for use with the arrangement shown in Figure 8.

' The present invention will now be described as applied to a pruning tool as disclosed in British Patent No. 608191, from which description the application of the invention to other tools having a scissor-like action against spring means will be readily understood.

It is preferred that the device according to the present invention should supersede the normal pivotal connection of the handle of the tool as indicated at A, Figure 1, since in the position shown, easy manipulation of the device by the thumb of the hand gripping the tool is possible.

Referring to Figure 2, a bush I having a flange v2 and a reduced diameter bore 3, provides a not only retains the bush I in position but also the bearing pin 9. Since the length of the bush is slightly in excess of the combined thickness of the handle extensions, it will be seen that free movement of the handles is permitted without 3 side play. The head ll! of the bearing pin 9 projects beyond the face of the adjacent handle extension and on the projecting part of the bearing pin is mounted a press button l3, the button being counterbored at M to receive the head l0. Referring to Figures 2 and 3, it will be seen that the press button is formed or provided with two diametrically opposite pins I5, the length of each pin being slightly 'less than the combined thickness of the handle extensions. Referring to Figure 4, a and b show portions of two arms forming the handle extension 4, while 0, d indicates the two arms forming the extension 5. In the construction of the tool shown in Figure '1, the arm is inserted in the bifurcation formed by the arms a and b as indicated in Figure 2. In the arms a and b are aligned holes l6 of suitable size to freely admit the two pins l5 and in the arm 0 are two arcuate slots I! having the same pitch as the holes I6, and of a width equal to that of the holes l6. Thearm d, which with c form the extension 5, is drilled similarly to a and b, :but the holes l6 are angularly displaced relatively to those in arms a and :b. .In the press button 13 is an annular groove 18 which seats and also centralizes a-spring 19, serving to load the button in an outward direction. When in this position, ,the ends of the ,pins I5 clear the arm at of the extension 5 .as will be seen from Figure 2. Since-the arms a and b move together and .arm cis provided with arcuate slots, it will be clear that the handles of the tool may be moved relatively to each other, but the extent .of such movement will be limited by the length .of the .slots 11. Therefore the extent of the opening and closing movements of the handles and consequently the blades is determined by the arcuate length of these slots. It will be noted that the holes l6 and also those in the arm d are in a .diametrical line disposed at an angle to the horizontal. This angle is .such that when the handles are closed together the holes will lie ,in a substantially horizontal 'line and will be coincident. Thus, if the button 13 is pushed in against the spring 1-9, the .pins l5 will enter the .holes in the plate dand lock the handles in the closed position. Since the tool is spring loaded, the pins will be retained in position by the friction between the walls of the holes in the arm (1 and the pins. The length of each arcuate slot I1 issuch that a slight further inward movement of the handle extensions .is possible and since the pins have a slight play in the holes, it is possible by slightly squeezing the handles together "to relieve the friction restraining the outward movement of the pins [5 by virtue of the spring I9. Thus, when the handles of the tool are locked together, it is only necessary to exert a slight pressure on them to effect their release. Although it is more satisfactory to use a pair of pins, the device could function with a single pin, one hole only being provided in each of the arms .a, b and d and a single slot in the arm 0. Further the holes I6 and slot [1 need not necessarily be in the position shown. They may occupy any other convenient position providing that the proper relationship between them is preserved.

As an alternative arrangement, the arm cmay be providedwith a pair of'holes which, when the handles are closed together, align with the holes in the arm a. In this case the pins l5 would be of such length as to .clear the arm 0 When the button is in its outward position. This arrangement has the disadvantage that owing to the rela- ':tively shortness of the pins they would tend to bind in the holes. This modification however can be employed where the pivotally connected parts each comprises a single member.

In the modification shown in Figure 5, the press button I3 is formed or provided with an arcuate lip 20. This lip is a sliding fit in a slot 2| in the arm a. The arm 0, immediately below the arm a, is formed with a corresponding slot 22, which coincides with the .slot 2| when the handles of the tool are closed together. Ex-

tending from the slot 22 is a recessed portion 23 having a depth approximately equal to half the thickness of the arm. When the press button is-in its outward position the lip extends into "the arm 0 and just clears the bottom of the recessed portion 23 thus permitting relative movement of the arms a and 0, but it will be apparent that'when the handles are closed together and the slots 2| and 22 are coincident the lip can be pressed to enter the slot 22 and thus lock the arms together. As in the previous construction, the fit of the lip in the slot 22 is such that slight inward pressure on the handles effects the release of the lip, and permits the opening of the handles. If desired, two diametrically opposite lips may be provided, the arms a and 0 being modified accordingly. It will be obvious that the lip or lips 20 may be superseded'by a pin or pins in which case holes would replace the slots in the arms. This arrangement could be utilized in the case where single superposed and pivotally connected parts are to be locked together, or limited, in their movements.

In the modification shown in Figures 8 and .9, each arm is formed with an enlargement 2.4 concentric with its pivot hole. In the periphery of the enlargement of arm .a is a slot 25 providing a sliding n1; for a lip .26 formed or provided on a press button 2], the diameter of which is equal to that of the enlargements. .In the enlargement of the arm 0 is an elongated slot .28, while in the enlargement of the arm 12, is a slot 29 which coincides with the slot 25 in the arm a, and inthe arm (1 is a slot .30 which can be brought intoalignment with the slots v25 and 29 when the handles of the tool are closed together. The construction in other respects is similar to that first described and function .in the same manner. If desired, the enlargements of arms a and 0 need only be slotted, the slots being so positioned that they coincide when the handles are closed together, the lip 26 being shortened accord'ingly.

In the case where the pivotally connected parts of a tool comprise a single member which is pivotally mounted in a bifurcation formed in another part, it will be obvious that three thicknesses of metal have .to be taken into consideration when incorporating a device according to the present invention. .In .such an arrangement, one of the members forming the bifurcation may be furnished with a pair of arcuate slots, .and the member which .moves within the bifurcation may be provided with a pair of apertures, while the other member forming the bifurcation may be provided with a pair of apertures which are suitably located so that they will coincide with the apertures in the member disposed within the bifurcation when the handles of the tool are closed together. In such an arrangement, the projections on the press button will normally just clear the most distant member. When, however, the handles .are closed together, and the apertures are brought into alignment, the press 15 button can be pressed to lock the members and consequently the handles together. The extent of the opening and closing of the handles will, of course, be determined by the length of the arcuate slots.

If desired, the member disposed within the bifurcation can be locked to one or other of the two arms forming the bifurcation by the arrangements previously described for locking two relatively movable arms.

What I claim is:

1. In a tool having a scissor-like action against spring means and including a plurality of superposed members, a bearing bush extending through said members and forming a pivot therefor, a headed bearing pin within the bush and projecting from a face of the tool, means for fixing both the bearing bush and the bearing pin in position, a spring loaded press button freely mounted on the projecting part of the bearing pin, at least one projection on the inside face of the press button, an arcuate slot for each projection in one of the aforesaid superposed members adapted to receive the projection and limit the opening and closing of the tool, apertures in the other superposed members for snugly receiving each projection, said apertures being located so that they will coincide with the projections when the handles of the tool are closed together to permit the projection or projections carried by the press button to enter the apertures when the press button is actuated, thereby locking the handles together, the retention of the projection or projections in the apertures being effected by the spring loading of the tool.

2. A tool having a scissors-like action, comprising superposed members, a pivotal connection between said members, a spring biasing said members apart about said pivotal connection, an element mounted on said pivotal connection for movement axially thereof, a spring biasing said element from said members, a projection on said element and extending toward said members, and an opening in each of said members for snugly receiving said projection, said openings being positioned in said members to coincide with said projection when said members are pressed to closed position, whereby the projection may be pressed into the openings to thereby lock the members together in closed position, the retention of the projection being effected by pressure exerted by the spring loading of the members.

3. A tool having a scissors-like action, comprising superposed members, a pivotal connection between said members, a spring biasing said members apart about said pivotal connection, an element mounted on said pivotal connection for movement axially thereof, a spring biasing said element from said members, a projection on said element and extending toward said members, and an opening in each of said members for snugly receiving said projection, said openings being positioned in said members to coincide with said projection when said members are pressed to closed position but very slightly short of extreme closed position, whereby the projection may be pressed into the openings to thereby lock the members together in closed position, the reten tion of the projection being eifected by lateral pressure exerted by the spring loading of the members and being released by pressing the members toward extreme closed position to enable the spring loaded element to withdraw the projection from said openings and. release the members.

4. A tool having a scissors-like action, comprising superposed members, at least one of said members comprising two spaced portions straddling a portion of the other member, a pivotal connection between said straddled portions of said members, a spring biasing said members apart about said pivotal connection, an element mounted on said pivotal connection for movement axially thereof, a spring biasing said element from said members, an opening in each of said straddled portions of said members and a projection on the inner side of said element and extending into at least one of said openings in each member, said openings being adapted to snugly receive said projection with the exception of one of said projection surrounding openings being an arcuate slot to permit limited relative movement between said members, said openings being positioned in said straddled portions to coincide with said projection when said members are pressed to closed position but very slightly short of extreme closed position, whereby the projection may be pressed into the openings to thereby lock the members together in closed position, the retention of the projection being effected by lateral pressure exerted by the spring loading of the members and being released by pressing the members toward extreme closed position to enable the spring loaded element to withdraw the projection from said openings and release the members.

LESLIE JOHN SMYTH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 869,949 Westerdahl Nov. 5, 1907 1,870,025 Rauh Aug. .2, 1932 1,987,935 Herrick Jan. 15, 1935 

